268 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 85 



tively slanting, axial riblets, Avhich develop into slender cusps at the 

 appressed summit and fine spiral threads, which render the axial rib- 

 lets slightly sinuose and somewhat thickened at their junction. This 

 sculpture extends over the inflated, strongly rounded, periphery and 

 base. Aperture ovate, slightly angulated posteriorly. Peristome 

 double, the outer very broadly flaringly expanded, somewhat radially 

 fluted and marked with concentric lines of growth; the inner de- 

 cidedly exserted, scarcely at all reflected. The space between the 

 parietal wall and the inner peristome is rather broad and is covered 

 by the outer peristome which is here inpinched to form a decided 

 channel, terminating in the deep pit, which plugs the umbilicus. 

 Operculum paucispiral, covered with a rather heavy calcareous gran- 

 ular deposit, which thins out toward the edge and disappears be- 

 fore reaching this. 



This species differs from C . (F.) foveata in being shorter and more 

 ovate and in having the space between the inner lip and the parietal 

 wall m.uch more deeply impressed. 



It comes from La Cumbre Mountain and from Los Cayitos la 

 Catalina north of San Diego Banos, the two localities representing 

 distinct subspecies, which the following key will help to differen- 

 tiate : 



KEY TO THE SUBSPECIES OF CHONDROTHYRA (FOVEOTHYRA) CUMBRENSIS 



Interrupted spiral bands very strong cumbrensis 



Interrupted spiral bands feeble catharina 



jCHONDROTHYRA (FOVEOTHYRA) CUMBRENSIS CUMBRENSIS, new subspecies 



Plate 17, Figure 6 



Shell varying considerably in size with the whorls inflated, strong- 

 ly rounded, and marked by rather pronounced interrupted spiral 

 zones on spire and base. These zones are also conspicuous on the 

 outer peristome of the last whorl, which here is unusually broad. 



The type, U.S.N.M. no. 492730, was collected by John B. Hender- 

 son in the Sierra la Cumbre. It has 4.3 whorls remaining and 

 measures: Length, 18.2 mm; greater diameter, 14.2 mm; lesser di- 

 ameter, 9.3 mm. 



CHONDROTHYRA (FOVEOTHYRA) CUMBRENSIS CATHARINA, new subspecies 



Plate 17, Figure 7 



This race averages smaller with the interrupted spiral bands nar- 

 rower and fainter and scarcely indicated on the outer peristome. 

 The umbilical pit here is unusually deep. 



